September 13, 2011

My RepRap is now complete

I finally completed my RepRap build, calibration, etc. I get good quality ( for a RepRap ) parts that aren’t blobby, but are a bit elliptical( due to elliptical gears on my motors ).

As of completing my RepRap project, I’ve begun work on my own printer design. I think the existing designs are way too complicated, and that the RepRap carriage design is too heavy and weak. It’s not a good printer for most people, and here’s why.

1. It’s too dang heavy. Once you get it built, it’s like 15 pounds, mostly in steel rods. Try carrying that a mile down the road. Your RepRap is essentially non-portable, and that takes a lot of the fun out of it, as printing is more fun in a group.

2. Other tool-heads don’t fit on it. You might be able to put a pen or marker on the cartesian section of the RepRap, maybe even a batter-powered dremel — but certainly not a router. You have all the control complexity and build complexity of a home-made CNC mill, without the usefulness of a CNC mill.

3. You’re dependent on eBay for parts, or have to over-pay for kits. Seriously, your best source of parts is eBay. Need linear bearings cheap? eBay. Want metal Z-couplers? eBay. Want metric rods? eBay. Hobbed bolts? you get the idea. You could buy a kit from Ultimachine, Makergear, botmill, tech zone, etc… Which all overcharge for their hot-ends, electronics, etc… Try buying a RepRap kit for $500 — I don’t think you can. Though, if you already had a RepRap, you could build a second one for less than $500 — probably around $300. The thing about eBay is the variance — some people there make great parts, and others make poor parts. You never know what you’ll get.

4. Too many build steps and tools. The RepRap is a complex build — you’re literally building a very weak CNC bot from hardware-store components. Most of the work is mind-numbing boring — wrapping heat-cores is most hated by me…

5. Too much maintenance work. I have to repair something every time I move my bot in my car. Something shakes loose — usually the electrical connections for the heat-core or thermsistor. Last time, I wanted to show off my rep-rap to some friends who came over. The PLA filament broke off in my extruder. I had to take apart the entire extruder — motors and all, and re-assemble. It took 1.5 hours. This is normal work with a RepRap — spend 80 hours building it, and another 2 hours every time you go to use it in repairs. I feel like I spend between 30 minutes and 2 hours every time I go to use the RepRap.

6. Non-useful products. I built my rep-rap to make useful things. I printed a pump design I had worked on, and discovered that mechanically, the thing couldn’t work. The PLA isn’t smooth enough to route a piston. Getting air-tight and thin walls is also not possible, as are long piston shafts, due to weaknesses in the material or limits of PLA prints.

The list goes on and on. The one thing I will say — I learned a lot, and may be able to build some mechanical parts for other projects with it. I think I can design a better 3d printer than the RepRap, Makerbot, or fab@home. To this end, I’ve begun work on “Imran’s better bot”. I don’t yet know what it’ll do, and I don’t know yet how well, but it’ll be easier to build, cheaper as a kit, and less/easier maintenance than either the MakerBot Thing-O-Matic or a Prusa Mendel. Wish me luck!